DIAMOND EDUCATION

Diamond Cut Guide

A diamond’s cut plays a major role in how it interacts with light and how much brilliance, fire and sparkle you see. Discover how proportions, symmetry, polish and facet arrangement influence a diamond’s appearance and learn what to consider when comparing cut quality.

What Is Diamond Cut?

Diamond cut describes how a diamond has been proportioned, faceted and polished to interact with light.

It should not be confused with diamond shape. Round, Oval, Princess, Emerald and Pear describe the outline or shape of a diamond, while cut refers to the quality and arrangement of its facets and proportions.

A well-cut diamond can reflect and return light effectively, creating the brilliance and sparkle associated with a beautiful diamond.

Why Is Diamond Cut Important?

Of the 4Cs, cut can have one of the strongest visual effects on a diamond.
Even a diamond with excellent colour and clarity may appear less lively when its proportions do not allow light to return effectively through the top of the stone.
A carefully cut diamond can appear brighter, more balanced and more visually impressive.

This Diamond Cut Guide explains how proportions, symmetry, polish and facet arrangement influence a diamond’s brilliance, fire and scintillation. Understanding these elements can help you compare diamonds more confidently and recognise why two diamonds of the same shape and carat weight may look very different.

How Light Creates Diamond Sparkle

A well-cut diamond interacts with light in three beautiful ways.

BRILLIANCE

The white light reflected from a diamond.

FIRE

Flashes of spectral colour created as light is dispersed.

SCINTILLATION

Flashes of light and dark as the diamond or viewer moves.

Diamond Cut and Proportions

Several proportions influence the appearance of a diamond. These elements work together to determine how light enters, travels through and exits the diamond, creating its brilliance, fire and sparkle.

These elements work together to influence how light enters, travels through and exits the diamond.

1. Table

The large, flat facet at the top of the diamond. The table affects how much light enters the stone and influences its overall brightness.

2. Depth

The total height of the diamond from the table to the culet. Depth works with the table, crown and pavilion to ensure light is reflected back through the top of the stone.

3. Crown

The upper portion above the girdle. The crown angle and height affect how light enters the diamond and contribute to its brilliance and fire.

4. Pavilion

The lower portion below the girdle. The pavilion angle and depth determine how light is reflected inside the diamond and back to the viewer, creating sparkle.

5. Girdle

The thin, outer edge that separates the crown from the pavilion. The girdle can range from very thin to very thick and helps protect the diamond while influencing its overall appearance.

Diamond Cut Grades

The cut grade shows how well a diamond’s proportions, symmetry and polish work together to interact with light. A higher cut grade generally delivers greater brightness, fire and sparkle, creating a more beautiful diamond.

EXCELLENT

Delivers exceptional brightness, fire and sparkle by maximising light return through precise proportions, symmetry and polish.

VERY GOOD

Offers excellent light performance with only slight compromises in proportions or finish compared to Excellent.

GOOD

Provides reasonable brightness and sparkle, but may show some light leakage due to less ideal proportions.

FAIR / POOR

May appear duller with reduced brightness and sparkle due to less ideal proportions, symmetry or polish, allowing more light to escape.

For additional information about diamond cut grading, see the Gemological Institute of America (GIA) guide to diamond cut.

Cut, Polish and Symmetry

These three elements work together to influence how light enters, travels through and exits the diamond, creating its brilliance and beauty.

CUT

Considers the overall way the diamond’s proportions and facets influence its appearance.

POLISH

Describes the quality of the diamond’s finished facet surfaces.

SYMMETRY

Refers to the alignment and consistency of the diamond’s facets.

Together, they contribute to the overall visual quality of the diamond.

Diamond Cut vs Diamond Shape

A diamond shape refers to the outline of the diamond, such as Round, Oval, Emerald, Princess or Pear.

Diamond cut quality, on the other hand, describes how well the diamond’s proportions, facets and angles are crafted to optimise light performance, determining its brilliance, fire and sparkle.

Same Shape

(Round Brilliant)

Different Cut Quality

(Different Brilliance)

Explore all diamond shapes in our detailed guide.

Does Cut Matter for Every Diamond Shape?

Yes, but cut evaluation varies by shape.

Round Brilliant diamonds are particularly associated with detailed cut grading and light-performance standards.

Fancy shapes such as Oval, Pear, Princess, Cushion and Emerald have different facet structures and proportions, so they should not all be judged in exactly the same way.

When comparing fancy shapes, proportions, symmetry and overall visual appearance become especially important.

ROUND

OVAL

PEAR

PRINCESS

CUSHION

EMERALD

Cut and the 4Cs

Cut should be considered together with colour, clarity and carat weight. A balanced diamond does not necessarily require the highest grade in every category. Many buyers prioritise cut because strong light performance can have a significant effect on how bright and lively a diamond appears.

4Cs OF DIAMONDS →